There are many situations in which checklists are used in an attempt to ensure safe and reliable operation of various types of equipment and systems. Some situations such as the operation of airplanes and other complex equipment and systems require several "normal" checklists that are used during different operational phases encountered when the airplane or other equipment is operating under normal conditions. Usually, these situations also employ several "non-normal" checklists that are used when various non-normal operating conditions are encountered.
The most prevalent type of checklists used today are printed paper checklists, which list checklist line items (checklist steps) on a series of cards or the pages of a book. Although simple in form, paper checklists are subject to several disadvantages and drawbacks. For example, if checklist items are skipped for later performance they may be forgotten. In addition, paper checklists do not provide an indication of checklist execution progress (i.e., the line items completed or not completed). Thus, completion of checklist line items may be forgotten if execution of the checklist is interrupted for any reason.
There have been various attempts to provide improved checklist systems, including devices for scrolling a paper checklist so that one checklist line item at a time is visible through a window or other opening. Electromechanical checklist systems have been provided, which generally include a plurality of switches that correspond to various line items. In such systems, the switches are actuated to indicate completion of the corresponding line item. Checklist systems that audibly read out line items of a selected checklist also have been developed. In such systems, the pilot or other crew member typically activate a check-off switch to proceed to the next checklist item. Electronic checklist system also have been provided, with such systems usually displaying checklist items on a cathode ray tube such as the airplane weather radar display. The checklist provided by these prior art electronic systems generally correspond to paper checklists that simply have been convened to electronic format.
Although the prior art has provided some advances over conventional paper checklists, a checklist system that provides reliable and rapid access, display and execution of both normal and non-normal checklists has not been developed or proposed. Further, the prior art has not provided a checklist system that easily accommodates switching between normal and non-normal checklists without risk of falling to complete all line items of each accessed checklist. Nor has a system been developed that lends itself to easily maintaining and modifying the system checklists.